2-chloroalkyl carbodimiides and a method of preparation

ABSTRACT

NOVEL CARBODIMIDES OF THE FORMULA   X-C(-R1)(-R2)-CH2-N=C=N-R3   WHEREIN X IS CHLORO OR BROMO, R1 AND R2 ARE HYDROGEN OR LOWER ALKYL, AND R3 IS A HYDROCARBYL OR A HALO- OR NITROSUBSTITUTED HYDROCARBYL RADICAL, ARE DISCLOSED. THE CARBODIMIDES ARE PREPARED BY REACTING (A) AN AZIRIDINE OF THE FORMULA   HN&lt;(-C(-R1)(-R2)-CH2-)   WITH (B) AN ISOCYANIDE OF THE FORMULA   R3-N=CX2.   NOVEL 1-AZIRIDINECARBOXIMIDOYL HALIDES OF THE FORMULA   R3-N=C(-X)-N&lt;(-C(-R1)(-R2)-CH2-)   ARE PREPARED ASS INTERMEDIATES IN THE PROCESS WHEN THE PROCESS IS CONDUCTED IN THE PRESENCE OF AN ACID ACCEPTOR, E.G. TTRIETHYLAMINE. SUCH INTERMEDIATES REARRANGE UPON WARNING, OR IN THE PRESENCE OF AN ACID, TO FORM THE CORRESPONDING CARBODIIMIDE. THE SUBJECT CARBONIIMIDES CAN BE HOMOPOLYMERIZED TO GIVE POLYMERS BEARING REACTIVE CHLOROALKYL GROUPS WHICH ARE THEMSELVES USEFUL AS CHELATING AGEENTS OR CAN BE. FURTHER REACTED WITH AMMONIA OR OTHER AMINES TO GIVEE QUATERNARY AMMONIUM-BEARING POLYMERS WHICH ARE USEFUL AS ION EXCHANGE RESINS OR CAN BE COPOLYMERIZEDD WITH OTHER KNOWN CARBODIMIDES TO FORM SIMILARLY USEFUL POLYMERS.

nited States Patent Office 3,754,032 Patented Aug. 21, 1973 ABSTRACT OF THE DISCLOSURE Novel carbodiimides of the formula wherein X is chloro or bromo; R and R are hydrogen or lower alkyl; and R is a hydrocarbyl or a haloor nitrosubstituted hydrocarbyl radical, are disclosed. The carbodiimides are prepared by reacting (a) an aziridine of the formula with (b) an isocyanide dihalide of the formula R --N=CX Novel l-aziridinecarboximidoyl halides of the formula are prepared as intermediates in the process when the process is conducted in the presence of an acid acceptor, e.g. triethylamine. Such intermediates rearrange upon warming, or in the presence of an acid, to form the corresponding carbodiimide.

The subject carbodiimides can be homopolymerized to give polymers bearing reactive chloroalkyl groups which are themselves useful as chelating agents or can be further reacted with ammonia or other amines to give quaternary ammonium-bearing polymers which are useful as ion exchange resins or can be copolymerized with other known carbodiimides to form similarly useful polymers.

BACKGROUND OF THE INVENTION Previous methods of preparing carbodiimides are summarized in Chemical Reviews, 67, 107-52 by F. Kurzer et al. The reference also contains a general summary of the known carbodiimides and their general utilities.

SUMMARY OF THE INVENTION It has now been discovered that novel asymmetric, 2- chloroalkyl carbodiimides of the general formula R2 wherein X is chloro or bromo; R and R are hydrogen or lower alkyl; and R is alkyl from 1 to 18 carbon atoms, cycloalkyl, e.g. cyclohexyl, aryl e.g. phenyl or naphthyl, alkaryl, e.g., alkyl substituted phenyl wherein the alkyl group has from 1 to 8 carbons, aralkyl, e.g., phenalkyl wherein the alkyl group contains 1 to 4 carbon atoms or B- naphthyl ethyl; or haloor nitro-substituted aryl, e.g., monoor dihalosubstituted phenyl or mononitrosubstituted phenyl, are conveniently prepared in the novel reaction comprising reacting by contacting (a) an aziridine of the formula R and R having the above meaning, with (b) an isocyanide dihalide of the formula R N=CX X and R having the above meaning. The subject carbodiimides are useful, for example, as monomers, polymerization promoters and as stabilizers for polymers which are subject to degradation due to heat, light and/or hydrolysis.

The novel process is represented by Equations I and/or II.

The direct process represented by (I) is generally an exothermic reaction. The product yields .from (I) may be lowered due to formation of polymeric by-products. The indirect process, (II), proceeds smoothly in the presence of an acid acceptor, e.g. triethylamine or pyridine, to form an intermediate, (iv), and a hydrohalide salt. The intermediate, (iv), is then easily isomeri'zed to form the desired product by merely (a) warming same to a temperature suificient to cause ring opening of the group, preferably in the presence of an inert solvent, or (b) forming an admixture of (iv) and a catalytic amount of an acid (eg HCl, H H010 H PO CF COOH, S0 A101 FeCl etc.), preferably in the presence of an inert solvent.

Isocyanide dihalides, as represented by (i) above, are a known class of compounds. Any compound within this class will be suitable for use in the subject process. Representative of such compounds include those in (i) wherein X is chloro and R is methyl, ethyl, butyl, cyclohexyl, octyl, dodecyl, octadecyl, phenyl, naphthyl, 0-, m-, or ptolyl, 3,5-dimethylphenyl, 4-t-butylphenyl, 4-octylphenyl, benzyl, phenethyl, [Si-naphthylethyl, 4 phenylbutyl, 4-nitrophenyl, 3-nitrophenyl, 2-fluorophenyl, 4-ch1orophenyl, 2,4- dichlorophenyl, 4-iodophenyl, and the like, and the corresponding compounds wherein X is bromo. The preferred isocyanide dihalide reactants are those in (i) wherein X is chloro, and most preferred are those wherein X is chloro and R is aryl or haloor nitro-substituted aryl.

Suitable aziridine reactants, (ii), include aziridine (ethylenimine), Z-methylaziridine, 2,2-dimethylaziridine, 2 ethylaziridine, 2 butylaziridine, and the like. Preferably, (ii) is aziridine, 2-methylaziridine or 2,2-dimethylaziridine, and most preferably, (ii) is aziridine.

The reacton temperature is generally selected between about 20 C. and 50 C. If the indirect process is followed, the temperature is preferably maintained between about -20 C. and 5 C. until (iv) is formed. At temperatures above about 50 C., the product yield in some instances is lowered due to the formation of poly meric by-products.

The stoichiometry of the reaction requires one mole of (i) per mole of (ii). However, an excess of either (i) or (ii) may be used, e.g. from 1 to 3 times the stoichiometric amount, or more. In the indirect process, at least one mole of acid acceptor is preferably included per mole of HX generated; it less than one mole of acid acceptor per mole of HX is used, the product yield of (iv) may be lowered due to formation of (iii) and/or polymeric by-products.

Pressure on the reaction is not critical. Atmospheric pressure is convenient and generally used.

The process, whether via Equation I or II, is preferably conducted in an inert solvent, such as carbon tetrachloride, methyl chloroform, chloroform, bromoform, benzene, toluene, hexane, etc. Carbon tetrachloride is preferred in most instances.

The subject carbodiimides, (iii), are generally liquids which may be used in substantially the same manner as were other carbodiimides (see Kurzer et al. above) to achieve similar results. Additionally, the subject carbodiimides can be homopolymerized to give unique polymers bearing reactive chloroalkyl groups which are themselves useful, as chelating agents, for example, or which can be further reacted with ammonia or other amines to give quaternary ammonium-bearing polymers which are useful for example, as ion exchange resins. Additionally, the subject carbodiimides may be copolymerized with other known carbodiimides to form polymers which are similarly useful. Such polymerization reactions occur upon heating the monomer-(s) or by warming the monomer(s) in the presence of a suitable catalyst. See, for example, US. Pat. 3,200,087 which describes certain carbodiimide polymers and polymerization catalysts which may be used herein.

SPECIFIC EMBODIMENTS The following examples further illustrate the invention.

Example l.-Preparation of N-(2-ehloroethyl)-N'-mnitrophenylcarbodiimide o1 EtsN mNO OHs-N=C C1; N-H 01 one.

25C.- l-A Gl'==-cH3GH3-N=C=N-ClH5-Noj A solution of aziridine (0.1 mole) and triethylamine (0.1 mole) in 75 ml. of carbon tetrachloride was added dropwise to a stirred, pro-cooled solution of m-nitrophenyl isocyanide dichloride (0.1 mole) in 75 ml. of carbon tetrachloride over a period of 1.5 hours; the temperature was maintained between C. and 5 C. during this time. The reaction mixture was warmed to room temperature and maintained at room temperature for 0.5 hour with continued stirring. Triethylamine hydrochloride was removed from the reaction mixture by filtration and the solvent and other volatiles were removed from the filtrate under reduced pressure. Compound l-A was thus obtained as a crystalline solid which, after recrystallization from diethyl ether, had a melting point of 68 70 C. The compound was stable at --5 C. to 0 C. for several months.

Elemental analysis showed:

C H ClN O .-Theory (percent): C, 48.0; H, 3.55; N, 18.7. Found (percent): C, 48.3; H, 3.57; N, 18.5.

A sample (0.3 g.) of l-A was warmed in a vessel equipped with a condenser and drying tube at a temperature of 68 C. for 12 minutes. The resulting yellow liquid, l-B, was produced in quantitative yield from l-A and in from 88-100% yield in a series of runs, based on starting materials. Elemental analysis showed:

C I-I ClN 0 .-'Iheory (percent): C, 48.0; H, 3.55. Found (percent): C, 48.5; H, 3.53.

In a subsequent experiment, a sample of 1-A was dissolved in acetone containing a catalytic amount of hydrochloric or perchloric acid. The conversion of l-A to l-B proceeded smoothly to completion in 1 hour at room temperature.

. Examples 2-6 2 l 1 Cl Dias n-A. R4 ClCR R:-OHz-N=C=N n-B y R4 TABLE 3 Example, 11 R R; vR4 Product description, n-A

E Light yellow liquid. H -Ol Crystalline solid; M.P'.

23 25 C- H H Light yellow liquid. H 3-NO: Amorphous solid. CH: 3-NO:

White crystals; MJ. I 26-28 C.

The products, n-B, were typically obtained by warming a solution of n-A in CCL; at 40 C. until the isomerization was complete, e.g. 14 hours and 31 hours for Examples 2 and 3, respectively. Alternatively, n-B was formed by stirring n-A in an acetone/hydrochloric or perchloric acid solution for 1 hour at room temperature. In both procedures, the product, n-B, was formed in essentially quantitative yield, based on nf'A and in 80- 10()% yield, based on starting materials.

In some instances, n-B was formed by merely warming n-A neat, e.g. Examples 2 and 6. Pursuant to this procedure, however, Example 6-A yieldeo a mixture of NO: We claim: 1. A compound of the formula wherein X is chloro or bromo; R and R are hydrogen or lower alkyl; and R is alkyl of from 1 to 18 carbon atoms, cyclohexyl, phenyl, naphthyl, alkyl substituted phenyl wherein the alkyl group has from 1 to 8 carbon atoms phenalkyl wherein the alkyl group contains 1 to 4 carbon atoms, p-naphthylethyl, monoor dihalosubstituted phenyl, or mononitrosubstituted phenyl.

2. The compound defined in claim 1 wherein R and 7 R are hydrogen or methyl.

3. The compound defined in claim 1 wherein X is chloro.

4. The compound defined in claim 3 wherein R and R are hydrogen or methyl.

5. The compound defined in claim 4 wherein R is phenyl, naphthyl, monoor dihalosubstituted phenyl or 6 R and R having the aforesaid meaning, with (b) an References Cit d isocyanide dihalide of the formula R N=CX X and FOREIGN PATENTS R having the aforesaid meamng 111 the absence of an acid acceptor wherein the reaction temperature is from 978,089 12/1964 Great Bummabout -20 C. to about 50 C. 5

9. A process for producing the compound defined in OTHER REFERENCES claim 1 comprising warming the compound Chemical Abstracts, vol. 43, column 1015 (d) (1949). j" X LEON ZITVER, Primary Examiner &=N R, 10 G. A. SCHWARTZ, Assistant Examiner R -R and X having the aforesaid meaning, to a tempera- US. Cl. X.R. ture sufiicient to promote ring-opening of the 260-239 N group. 

